JP5410815B2 - Metal plate laminate film - Google Patents

Description

  The present invention relates to a metal plate laminating film used for the purpose of preventing corrosion inside metal containers such as soft drinks, beer and canned foods, a film laminated metal plate obtained by laminating such a film on a metal plate, and such a film. The present invention relates to a metal container obtained by forming a laminated metal plate. In particular, the present invention relates to a metal plate laminating film excellent in adhesion to a metal plate, a film laminated metal plate excellent in releasability and resistance to cracking, and a metal container excellent in impact resistance.

  Generally, metal containers such as soft drinks, beer, and canned foods are manufactured by drawing and ironing a metal plate laminated with a resin film to prevent corrosion. For the resin film used for such applications, adhesion (property that the resin film does not peel from the laminated metal plate), releasability (film laminated metal plate was drawn and wrung with a processing punch to form a metal container. Later, the metal container can be easily removed from the processing punch), resistance to cracking (property of occurrence of bumping phenomenon (so-called cracking) due to heat treatment during can making), and impact resistance (impact such as dropping when transporting the metal container) The property that the film on the inner surface of the metal container is not broken even if is added) is required.

  In order to satisfy this requirement, for example, in Patent Document 1, a film for laminating a metal plate having a two-layer structure comprising a polyester layer mainly composed of polyethylene terephthalate and / or polyethylene isophthalate and a layer containing polyester and a thermoplastic elastomer is blended. Has been proposed. However, although this film is excellent in impact resistance, adhesion, releasability, and resistance to cracking were not sufficient.

  Patent Document 2 proposes a metal plate laminating film having a two-layer structure comprising a crystalline polyester layer and a layer formed by mixing a crystalline polyester and an olefin polymer. However, although this film is also excellent in impact resistance, adhesion, releasability, and resistance to cracking were not sufficient.

  As described above, a metal plate laminating film that is highly satisfactory in all of adhesion, releasability, crack resistance and impact resistance has not yet been obtained.

JP-A-8-156182 JP 2004-285343 A

  The present invention was devised in view of the current state of the prior art, and its purpose is to provide a metal plate laminating film that highly satisfies all of adhesiveness, releasability, armpit resistance, and impact resistance. There is to do.

  In order to achieve the above object, the present inventors have intensively studied a suitable layer structure of a metal plate laminating film. As a result, the three-layer structure metal plate laminating film in which a specific layer is combined has a good adhesion and release property. The present inventors have found that they are highly satisfied with all of moldability, resistance to warp and impact resistance, and have completed the present invention.

That is, according to the present invention, a resin layer comprising 20 to 80/80 to 20% by weight of crystalline polyester resin composed of crystalline polyethylene terephthalate / crystalline polybutylene terephthalate containing 500 ppm or more of an antioxidant and a lubricant, respectively. (I) and a resin layer (II) in which an olefin polymer is dispersed in the form of particles having an average particle diameter of 3.0 to 5.0 μm in a polyester resin having a melting point of 180 ° C. or higher are further laminated. II) is formed by laminating a resin layer (III) made of a water-dispersed copolyester resin on the side intended to be bonded to the metal plate, and the total thickness of the resin layer (I) and the resin layer (II) Is 10-50 μm, the ratio of the thickness of the resin layer (I) / resin layer (II) is 30-70 / 70-30, the thickness of the resin layer (III) is 5-40 nm, Mixing weight ratio of the polyester resin and olefin-based polymer in the lipid layer (II) is 91: 9-99: metal plate laminated film is provided which is a 1.

Preferred embodiments of the metal plate laminating film of the present invention are as follows.
(1) A film for laminating a metal plate is laminated on a metal plate, remelted by heat equal to or higher than the melting point of the film, and then rapidly cooled, and then the adhesion strength between the film and the metal plate is 18 N / 15 mm or more. It is.
(2) The melting point of the resin layer (I) is 200 to 260 ° C., and there are at least two melting peaks of the resin layer (I).
(3) The Tg of the water-dispersed copolymer polyester of the resin layer (III) is 40 to 80 ° C.
(4) The olefin polymer is made of polyethylene and / or ethylene copolymer.

  In addition, according to the present invention, it is obtained by laminating the metal plate laminating film on a metal plate, and obtained by molding the film laminated metal plate. A metal container is provided.

  The film for laminating a metal plate of the present invention has particularly good adhesion when laminated on a metal plate, and the obtained film-laminated metal plate is excellent in releasability and resistance to cracking. Further, the metal container obtained by molding this film-laminated metal plate has extremely good impact resistance.

Hereinafter, the metal plate laminating film of the present invention will be described in detail.
The metal plate laminating film of the present invention comprises a resin layer (I) containing an antioxidant and a lubricant in a specific crystalline polyester resin, and an olefin polymer dispersed in a polyester resin having a specific melting point. The resin layer (II) and the resin layer (III) made of water-dispersed polyester resin are laminated in this order.

  The crystalline polyester resin constituting the resin layer (I) is composed of crystalline polyethylene terephthalate and crystalline polybutylene terephthalate. Crystalline polyethylene terephthalate contributes to heat resistance and aroma retention, and crystalline polybutylene terephthalate contributes to moldability and whitening resistance. The blending ratio of the crystalline polyethylene terephthalate and the crystalline polybutylene terephthalate in the resin layer (I) is 20 to 80/80 to 20% by weight, preferably 30 to 70/70 to 30% by weight. If the blending ratio is less than the above range, whitening may occur during hot water treatment. On the other hand, if the blending ratio exceeds the above range, the film-forming property is lowered, which is not preferable from the viewpoint of productivity and raw material cost, and is not preferable.

  In the metal plate laminating film of the present invention, the resin layer (I) preferably has a melting point of 200 ° C to 260 ° C. If the melting point of the resin layer (I) is less than the above range, there is a possibility that the releasability and resistance to cracking will not be sufficient. On the other hand, if the melting point of the resin layer (I) exceeds the above range, the balance at the time of melt extrusion with the resin layer (II) may be lost and the film forming property may be deteriorated.

  In the metal plate laminating film of the present invention, it is preferable that at least two melting peaks of the resin layer (I) exist. When the transesterification proceeds between the crystalline polyethylene terephthalate and the crystalline polybutylene terephthalate of the resin layer (I) during mixed melt extrusion, there is a possibility of causing whitening and a decrease in releasability during hot water treatment. By preventing the ester reaction from proceeding during mixed melt extrusion, the resin layer (I) can have at least two melting peaks. As for the melting peak, at least the low-temperature side melting peak is 210 ° C or higher, and the high-temperature side melting peak is 240 ° C or higher, so that sufficient release from the processing punch of the resin on the inner surface of the can is ensured in drawing and ironing processing. This is preferable.

  The production method of crystalline polyethylene terephthalate and crystalline polybutylene terephthalate constituting the resin layer (I) is not particularly limited, and any of known polyester production methods such as a transesterification method, a direct polymerization method and a solid phase polymerization method can be used. Although it can be used, in order to reduce oligomer precipitation from the resin during retort processing that is performed after filling the contents in a metal container, a solid-phase polymerization method under reduced pressure or in an inert gas atmosphere is used. It is particularly preferable to do this.

  Examples of the polymerization catalyst for the polymerization include antimony oxide, germanium oxide, and a titanium compound. In addition to these polymerization catalysts, the polymerization system is provided with Mg salts such as magnesium acetate and magnesium chloride, Ca salts such as calcium acetate and calcium chloride, acetic acid in order to impart electrostatic adhesion during melt extrusion. Mn salt such as manganese and manganese chloride, Zn salt such as zinc chloride and zinc acetate, Co salt such as cobalt chloride and cobalt acetate as the total amount of each metal ion, 300 ppm or less, phosphoric acid or phosphoric acid trimethyl ester, triethyl phosphate It is also possible to add phosphate ester derivatives such as esters in the range of 200 ppm or less as phosphorus atoms. When the total amount of metal ions other than the above polymerization catalyst exceeds 300 ppm and the amount of phosphorus exceeds 200 ppm, not only is the resulting polyester colored significantly, but the heat resistance and hydrolysis resistance of the polyester may also decrease. Therefore, it is not preferable.

  The crystalline polyester resin of the resin layer (I) of the film for laminating a metal plate of the present invention needs to contain an antioxidant in order to improve the armpit resistance in the can making process. “Waki” refers to a phenomenon in which minute crater-like defects occur due to poor heat resistance in the remelting process, the resin layer becomes fluidly movable, the resin is not uniform, or the properties are different. If there is something, it will be easy to generate "armpits". The kind of antioxidant is not specifically limited, For example, a hindered phenolic antioxidant etc. can be used. The content of the antioxidant needs to be 500 ppm or more. If it is less than 500 ppm, sufficient armpit resistance cannot be achieved. The upper limit of the antioxidant content is not particularly limited, but is usually about 2000 ppm. Even if it exceeds 2000 ppm, the resistance to armpits does not improve any more, which is disadvantageous in terms of cost.

  In addition, the crystalline polyester resin of the resin layer (I) needs to contain a lubricant in order to improve the releasability (molding processability). The type of the lubricant is not particularly limited, and for example, synthetic waxes such as polyolefin wax and polyester wax, and natural waxes such as carnauba wax can be used. The content of the lubricant needs to be 500 ppm or more. If it is less than 500 ppm, the dynamic friction coefficient with the film surface using a steel ball in a 50 ° C. environment as a slider does not become 0.30 or less, and sufficient releasability (moldability) cannot be achieved. The upper limit of the content of the lubricant is not particularly limited, but is usually about 2000 ppm. Even if the content exceeds 2000 ppm, the releasability (molding processability) is not further improved, which is disadvantageous in terms of cost.

  The crystalline polyester resin of the resin layer (I) can contain a lubricant composed of inorganic or organic particles in order to further improve the releasability. The average particle size of the lubricant is not particularly limited, but is preferably 1 to 3 μm. If the thickness is less than 1 μm, the effect of improving the releasability may not be exhibited. On the other hand, if it exceeds 3 μm, the effect of improving the releasability is saturated, but the lubricant may fall off due to wear, or the film may break when laminated with a metal plate. Further, the content of the lubricant is not particularly limited, but is preferably 0.01 to 2% by weight with respect to the crystalline polyester resin of the resin layer (I). If it is less than 0.01% by weight, the effect of improving the releasability may not be exhibited. On the other hand, if the content exceeds 2% by weight, the effect of improving the releasability does not change, which is disadvantageous in terms of cost.

  The crystalline polyester resin of the resin layer (I) further contains additives such as a heat stabilizer, an ultraviolet absorber, a plasticizer, a pigment, an antistatic agent, and a crystal nucleating agent in addition to the above-described additives. be able to.

  Next, the resin layer (II) will be described. The resin layer (II) has a structure in which an olefin polymer is dispersed in a polyester resin having a specific melting point. A conventionally well-known thing can be used as this polyester resin. The melting point of this polyester is 180 ° C. or higher, preferably 200 ° C. or higher. If the melting point is less than the above range, the heat resistance is insufficient in the bonding step, which is not preferable. Moreover, although the upper limit of melting | fusing point of this polyester resin is not specifically limited, Usually, it is about 240 degreeC. When the melting point exceeds the above range, the moldability is insufficient, which is not preferable. The polyester resin of the resin layer (II) may be the same as the crystalline polyester resin of the resin layer (I). Since the polyester resin of the resin layer (II) can be produced in the same manner as the crystalline polyester resin of the resin layer (I), description of the production method is omitted.

  In the resin layer (II), it is necessary that the olefin polymer is dispersed in the above-described polyester resin in the form of particles having an average particle diameter of 0.2 to 5.0 μm. The olefin polymer is preferably polyethylene and / or ethylene copolymer, for example, low density polyethylene, medium density polyethylene, high density polyethylene, linear low density polyethylene, ultra high molecular weight polyethylene, polypropylene, ethylene. -Propylene copolymer, ethylene-butene copolymer, ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, ethylene-methyl acrylate copolymer, ethylene-methyl methacrylate copolymer, ethylene-acrylic acid Copolymers, ethylene-methacrylic acid copolymers, ethylene-ethyl acrylate-maleic anhydride copolymers, ethylene-maleic anhydride graft copolymers, ethylene-vinyl alcohol copolymers, and the like can be used. As the olefin polymer, a resin selected from the above can be used alone, but two or more kinds of resins are preferably used in combination.

  In the film after remelting, the olefin polymer blended in the polyester of the resin layer (II) is dispersed in the form of particles, and the average particle size of the dispersed particles is 0.2 to 5.0 μm. It is necessary to combine properties, releasability, armpit resistance and impact resistance. A more preferable range of the average particle diameter is 0.2 to 4.0 μm. If the average particle size is less than the above range, the impact resistance is inferior, and if the average particle size exceeds the above range, the armor resistance may be lowered.

  Dispersing the olefin polymer to an average particle size in the above range can be performed by controlling the conditions of melt kneading when blending the olefin polymer with the polyester. This condition depends on the type and amount of the selected polyester resin and olefin polymer. For example, when extruding a melt blended resin in a layer form from a T die and molding a film, a twin screw extruder rather than a single screw Is preferably used.

  In addition, as an example of selection of the olefin polymer for dispersing the olefin polymer in the polyester resin with an average particle diameter in the above range, a polyolefin containing no functional group and a polyolefin containing a functional group are included. It is preferable to use two or more types of olefin polymers in combination. By blending the olefin-based polymer having the above-described configuration into a polyester resin, an olefin-dispersed particle having a core / shell structure in which the central layer (core) is a non-functional group-containing polyolefin and the surface layer (shell) is a functional group-containing polyolefin. It is thought to be produced and effectively finely dispersed. As specific examples, combined use of polyethylene and ethylene- (meth) acrylic acid copolymer, and combined use of ethylene-α-olefin copolymer and ethylene-α-olefin- (meth) acrylic acid copolymer are preferable. Here, the content of the polyolefin containing a functional group is desirably in the range of 1 to 10 parts by weight with respect to 100 parts by weight of the polyester resin. If the amount is less than 1 part by weight, the amount is insufficient to form the shell portion, and if the amount exceeds 10 parts by weight, the effect is saturated because the effect is saturated with respect to the formation of the shell portion.

  As a preferable functional group, a polar functional group having an effect of increasing the affinity with the polyester resin to be blended can be used, and examples thereof include a carboxyl group, a glycidyl group, and an acid anhydride group. Specific examples of polyolefins containing such functional groups include ethylene-α, β such as ethylene- (meth) acrylate copolymers and ethylene- (meth) acrylic acid ester copolymers produced by various production methods and catalysts. -An unsaturated carboxylic acid copolymer can be illustrated.

  The blending weight ratio of the polyester resin and the olefin polymer in the resin layer (II) is preferably 91: 9 to 99: 1, and particularly preferably 91: 9 to 95: 5. If the blending ratio of the olefin polymer is less than the above range, the impact resistance improving effect may be insufficient. Further, if the blending ratio of the olefin polymer exceeds the above range, a bumping phenomenon (so-called “waki”) may easily occur during the heat treatment (remelt) during can manufacturing.

  Next, the resin layer (III) will be described. The resin layer (III) is composed of a water-dispersed polyester resin. Here, the water-dispersed copolyester resin refers to a copolyester resin that is insoluble in water but can be dispersed or dissolved in an aqueous solvent.

  Specifically, the water-dispersible polyester resin includes a monomer having a hydrophilic group (such as a hydroxyl group, an amino group, a carboxyl group, a sulfonic acid group, a derivative thereof, a metal base, or an ether group) in the molecule. A polymerized polyester resin may be mentioned. Specific examples of such monomers include sulfones such as polyethylene glycol, polypropylene glycol, glycerin, polyglycerin, 5-sulfoisophthalic acid, 4-sulfonaphthalene-2,7-dicarboxylic acid, and 5 (4-sulfophenoxy) isophthalic acid. Examples thereof include acid-containing monomers and metal salts thereof. Among these, sulfonic acid group-containing monomers are preferable.

  Further, as the water-dispersed copolymer polyester resin, a polyester resin obtained by graft-polymerizing a vinyl monomer having a hydrophilic group (carboxyl group, hydroxyl group, sulfonic acid group, amide group, etc.) to the copolymer polyester, By graft-polymerizing a vinyl-based monomer having a group that can be changed to a hydrophilic group (an acid anhydride group, a glycidyl group, a chloro group, etc.) onto a copolymerized polyester, and then changing this group to a hydrophilic group The polyester resin obtained is also mentioned. Among these, those having a carboxyl group as a hydrophilic group, for example, those obtained by copolymer polyester polymerization of vinyl monomers such as acrylic acid, methacrylic acid, maleic acid, and salts thereof are preferable.

  In the metal plate laminating film of the present invention, excellent adhesion strength with the metal plate can be realized by providing the resin layer (III) made of the water-dispersed copolymer polyester resin. Specifically, a metal plate laminating film is laminated on a metal plate, remelted by heat equal to or higher than the melting point of the film, then rapidly cooled, and the measured adhesion strength between the film and the metal plate is 18 N / It can be 15 mm or more. Further, since the water-dispersed copolyester resin is dispersed in an aqueous solvent, it is not necessary to use an organic solvent for forming the resin layer (III), and adverse effects on the human body and the environment can be reduced.

  The water-dispersed copolyester resin constituting the resin layer (III) preferably has a Tg of 40 to 80 ° C, and more preferably has a Tg of 50 to 70 ° C. If the Tg is less than the above range, the handling after coating is poor and blocking is not preferable. On the other hand, if Tg exceeds the above range, the initial adhesion with the metal is lowered, which is not preferable.

  In the metal plate laminating film of the present invention, the total thickness of the resin layer (I) and the resin layer (II) is from 10 to 50 μm, preferably from 15 to 50 μm, from the viewpoint of the balance between the coating effect (rust prevention) and economy. 40 μm. Moreover, the ratio of the thickness of resin layer (I) / resin layer (II) is 30-70 / 70-30, Preferably it is 60-40 / 40-60. During high-temperature processing such as remelt processing, bumping of the resin layer (so-called cracking) is likely to occur, but this phenomenon is suppressed by setting the layer thickness ratio of the resin layers (I) and (II) within the above range. It is possible to achieve both formability and impact resistance even if the processing conditions when forming through processing such as ironing become severe.

  The resin layer (III) has a thickness of 5 to 40 nm, preferably 7 to 30 nm. If the thickness of the resin layer (III) is less than the above range, the resin layer (III) may cause so-called film cracking and an appropriate film may not be formed. Further, if the thickness of the resin layer (III) exceeds the above range, the interlayer strength of the resin layer (III) itself is weakened, so that peeling or floating may occur at the time of can making, and the yield may be lowered.

Next, an example of a method for producing the metal plate laminating film of the present invention will be described.
First, the crystalline polyester resin of the resin layer (I), and the polymer obtained by dry blending or melt-mixing the polyester resin and olefin polymer of the resin layer (II) are each in a known single-screw or twin-screw extruder. And then melted in the system to form two layers, and a T-die is used to obtain a layered molten resin film, or molten resins sent from different flow paths are joined in the T die. A molten resin film having a layer structure is obtained.

  Next, this molten resin film is cooled and solidified. As a cooling and solidification method used in this case, a known method in which a resin melted in a layer form from a T die is brought into contact with a rotated cooling roll can be employed. Specifically, when the molten resin is brought into contact with the cooling roll, a method of forcibly blowing air, a method of adhering with static electricity, or a method of making the surroundings where the molten resin comes into contact with the cooling roll into a reduced-pressure atmosphere is adopted. Is preferred.

  After cooling and solidifying, the cooled and solidified product is subjected to longitudinal stretching of 1.3 to 6.0 times at a temperature not lower than the glass transition point of the polyester and lower than the cold crystallization temperature. In order to further improve productivity, it is preferable to carry out transverse stretching. Next, in order to control the heat shrinkage rate, the resin layer is heat-treated for 1 to 20 seconds at a relaxation rate of 3% or more and in a temperature range of 50 ° C. or higher and polyester melting point −20 ° C. to polyester melting point −80 ° C. or lower. A laminate film of (I) and resin layer (II) is obtained.

  Next, both ends of the film are cut and removed, and then cut into a necessary width to obtain a roll-shaped film. In the present invention, it is possible to reuse the raw material obtained by the method of pressing or melting the remaining film obtained by slicing the remaining film and / or the roll film obtained by cutting or removing the above-mentioned film. Is possible. In general, the reusable raw material is preferably used for the resin layer (II) in order to maintain the characteristics of the film. The reuse rate is not particularly limited, but 5 to 50% is preferable.

  Next, a water-dispersed copolyester resin is dispersed or dissolved in an appropriate aqueous solvent to prepare a coating solution for the resin layer (III). The coating solution is divided into the resin layer (I) and the resin layer (II). The surface of the resin layer (II) of the laminate is coated by a gravure coating method or the like. This coating treatment may be performed on a stretched film during (inline) formation of a laminate of the resin layer (I) and the resin layer (II), or may be performed on a film after film formation (offline). May be.

  The film-laminated metal plate of the present invention can be obtained by laminating the laminating film on the metal plate of the present invention thus obtained. As the metal plate for laminating the film, a steel plate, an aluminum plate or an aluminum alloy plate can be used. As a method for obtaining a film laminated metal plate, these metal plates are heated to a melting point of polyester of −20 ° C. or higher and a melting point of polyester of + 150 ° C. or lower, and then a laminate roll is used to form the metal plate laminating film of the present invention. A method of laminating on a plate, and subsequently heating the laminated metal plate at a melting point of polyester + 10 ° C. or higher and a melting point of polyester + 60 ° C. or lower (so-called remelt treatment), followed by water cooling and / or air cooling.

  The film laminated metal plate of the present invention is preferably laminated so that the resin layer (III) side of the metal plate laminate film of the present invention is bonded to the metal plate. By laminating in this way, the resin layer (I) having releasability constitutes the surface layer of the film laminate metal plate, and the releasability with the punch can be exhibited at the time of drawing.

  The metal container of the present invention is obtained by molding the film laminate metal plate of the present invention thus obtained. Specifically, the film laminate metal plate of the present invention can be obtained by drawing and ironing.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further more concretely, this invention is not limited by these Examples. The evaluation methods used in the examples are as follows.

[Evaluation method]
(1) Melting point of polyester After heating and melting the polyester composition at 300 ° C. for 5 minutes, 10 mg of a sample obtained by quenching with liquid nitrogen was used, and 10 ° C. using a differential scanning calorimeter (DSC) in a nitrogen stream. An exothermic / endothermic curve (DSC curve) was measured at a rate of temperature rise per minute, and the apex temperature of the endothermic peak accompanying melting was defined as the melting point Tm (° C.) of the polyester.

(2) Intrinsic viscosity (IV)
Intrinsic viscosity was measured in orthochlorophenol at 25 ° C.

(3) Thickness of water-dispersed copolyester resin layer The thickness of the water-dispersible copolyester resin layer was measured by a weight method based on a sample cut out from the film. After measuring the weight of the cut sample, the water-dispersed copolyester resin layer was wiped off using an arbitrary solvent, the weight of the subsequent sample was measured, and the specific gravity of the resin was determined from the weight difference before and after wiping. 1 is used to calculate the thickness of the water-dispersed copolyester resin layer.

(4) Average particle diameter of olefinic polymer In Examples and Comparative Examples, a polyester resin and an olefinic polymer were melt-kneaded with an extruder and a sheet obtained by extruding into a layer from a T-die was wrapped in an epoxy resin. What was buried and hardened was incised by a cryomicrotome in a cross section parallel to each stretching direction, and an ultrathin section was prepared. This was dyed with ruthenium oxide, held at room temperature for 10 minutes, then carbon-deposited and observed with a transmission electron microscope. The average particle diameter of the dispersed olefin polymer was determined by weighted average of the long diameters using an image analyzer (V10, manufactured by Toyobo Co., Ltd.).

(5) Adhesive strength after remelting A remelt aluminum plate was treated with dilute hydrochloric acid to dissolve and remove a part of the aluminum metal portion, and only the film was taken out. With this as a trigger, the film / aluminum metal plate was peeled off. After sufficiently peeling, a reinforcing material was pasted so that the film did not stretch, and cutting was performed to a width of 15 mm. The sample was subjected to measurement of peel strength (adhesion strength) at a tensile rate of 5 mm / min using a tensile tester.

(6) Releasability between can inner film and processing punch After forming a laminated aluminum plate into a cup by drawing, n = 100 cans are formed by redrawing and ironing at a speed of 60 cans / min. The degree of buckling occurring in the film was visually observed. The evaluation criteria were set as follows.
○: Buckling has not occurred in the can opening △: Buckling has occurred in about 1/3 of the circumference of the can opening ×: Buckling has occurred in more than 1/3 of the circumference of the can opening

(7) Impact resistance I
A can obtained by making a remelt aluminum plate was heated at 280 ° C. for 40 seconds and then rapidly cooled in water. Thereafter, 10 pieces of 7 cm square samples were cut out from the center of the body wall of the can. A weight (600 g) having a tip diameter of 10 mm was dropped from a height of 10 cm onto the surface corresponding to the outer surface of the sample, and the impact was immersed in an aqueous solution of sodium hydroxide. Was measured for 30 seconds and evaluated according to the following criteria.
○: 7 or more sheets have a current value of less than 1 mA Δ: 7 sheets or more have a current value of 1 mA or more X: 7 sheets or more have a current value of 5 mA or more

(8) Impact resistance II
A can obtained by making a remelt aluminum plate was heated at 280 ° C. for 40 seconds and then rapidly cooled in water. Thereafter, a 7 cm square sample was cut out from the center of the body wall of the can. A weight (600 g) having a tip diameter of 10 mm is dropped from a height of 10 cm onto the surface corresponding to the outer surface of the sample, and the sample is placed on a glass container filled with 7% dilute hydrochloric acid. It set | placed in the state immersed, and the corrosion state of the convex part was visually observed after 3 days. The evaluation criteria were set as follows.
○: Corrosion of the convex part is not generated ×: Corrosion of the convex part is generated

(9) Waki resistance The appearance of the remelt aluminum plate was observed. The evaluation criteria were set as follows.
○: Waki has not occurred ×: Waki has occurred

  Next, the manufacturing method of the crystalline polyester resin used for the Example and the comparative example, the kind of olefin-type polymer, and its acquisition place are demonstrated.

(1) PET: Polyethylene terephthalate (IV = 0.73)
In a reactor equipped with an inlet, a thermometer, a pressure gauge, a distillation tube with a rectifying column, and a stirring blade, 82 parts by weight of ethylene glycol (molar ratio of ethylene glycol / terephthalic acid = 100 parts by weight of terephthalic acid = 2.2) 0.05 mol% germanium oxide as the Ge element, 0.05 mol% magnesium acetate as the Mg element, and 0.23 amorphous silica particles having an average particle diameter of 1.3 μm with respect to the acid component Part by weight was charged, nitrogen was introduced with stirring, the pressure inside the system was kept at 0.3 MPa, and the esterification reaction was carried out at 230 ° C. to 250 ° C. while distilling off the generated water outside the system. After completion of the reaction, 0.04 mol% of trimethyl phosphate as P element was added at 250 ° C, and the pressure was gradually reduced while the temperature was raised, and a polycondensation reaction was carried out under a vacuum of 275 ° C and 1.0 hPa or less to obtain an intrinsic viscosity. 0.73 polyethylene terephthalate (PET) was obtained.

(2) PBT: polybutylene terephthalate (IV = 1.0)
In a reactor equipped with an inlet, a thermometer, a pressure gauge, a distillation tube with a rectifying column, and a stirring blade, 86 parts by weight of 1,4-butanediol (1,4-butane with respect to 100 parts by weight of terephthalic acid) Diol / terephthalic acid molar ratio = 1.6), 0.05 parts by weight of tetranormal butyl titanate, 0.025 parts by weight of butyl hydroxytin oxide, and 190 ° C to 230 ° C while distilling generated water out of the system The esterification reaction was carried out. After completion of the reaction, 0.05 parts by weight of tetranormal butyl titanate and 0.025 parts by weight of phosphoric acid were added, and a polycondensation reaction was carried out at 250 ° C. under reduced pressure (1.0 hPa or less) to obtain polybutylene terephthalate (PBT, limit A viscosity of 1.0) was obtained.

(3) PET-I (10): Polyethylene terephthalate / isophthalate (10 mol% repeating unit of ethylene isophthalate, IV = 0.73)
A polyethylene terephthalate / isophthalate (PET-I (10)) was prepared by the same method as that for polyethylene terephthalate (PET) except that 100 parts by weight of terephthalic acid was changed to 90 parts by weight of terephthalic acid and 10 parts by weight of isophthalic acid. Intrinsic viscosity 0.73) was obtained.

(4) Olefin A: Low density polyethylene (Sumitomo Chemical Co., Sumikasen G401) was used.
(5) Olefin B: An ethylene-acrylic acid copolymer (manufactured by Dow Chemical Company, Primacol 3440) was used.
(6) Olefin C: An ethylene-methacrylic acid copolymer (manufactured by Mitsui DuPont Polychemical Co., Ltd., Nucrel N1108C) was used.
(7) Olefin D: An ethylene-ethyl acrylate copolymer (Mitsui DuPont Polychemical Co., Ltd., Evaflex A712) was used.
(8) Olefin E: Ethylene-1-butene copolymer (manufactured by Nippon Synthetic Rubber Co., Ltd., EBM2041P) was used.

[Example 1]
Resin layer (I): A raw material obtained by adding 1000 ppm of hindered phenolic antioxidant (Irganox 1010 manufactured by Ciba Specialty Chemicals) and 1000 ppm of polyethylene wax to PET / PBT = 40/60 (wt%) as a main raw material. What was dried at 100 ° C. for 24 hours was used.
Resin layer (II): obtained by pre-kneading PET-I (10) / olefin A / olefin B = 94/3/3 (% by weight) as a main raw material at 270 ° C. using a biaxial vent type extruder. The raw material was dried at 100 ° C. for 24 hours.
The resin layers (I) and (II) are each melted at 270 ° C. using a single-screw extruder, and then merged in the flow path, extruded in a layer form from a T-die onto a cooling roll, and an unstretched sheet of laminated resin Got. The unstretched sheet was stretched 3.5 times in the machine direction at a preheating temperature of 80 ° C. and a stretching temperature of 100 ° C., and further stretched by 4.0 times in the transverse direction at a preheating temperature of 80 ° C. and a stretching temperature of 100 ° C. Heat treatment was performed at 0 ° C. for 8 seconds to obtain a double-layer film having a thickness of 20 μm. The ratio of the thickness of each layer of this film was resin layer (I) / resin layer (II) = 60/40.

  An aqueous dispersion type coating solution of sulfonic acid group-containing copolymer polyester (Toyobo's Vylonal), adjusted to have a coating layer thickness after drying of 10 nm by a gravure coating method, was applied to the resin layer (II ) Side and dried at 160 ° C. for 8 seconds to obtain a metal plate laminating film provided with a water-dispersed copolyester resin layer (III). The structure of this film is shown in Table 1.

  After laminating this metal plate laminating film on a 3004 series aluminum alloy plate (thickness 0.26 mm) heated to 250 ° C. using the water-dispersed copolyester resin layer (III) as the bonding surface, The laminate aluminum plate was produced by quenching and curing. Next, this laminated aluminum plate was heated at 275 ° C. for 40 seconds, then air-cooled, and then quenched in water to obtain a remelt aluminum plate.

  After applying the molding lubricant to the remelt aluminum plate thus obtained, it was heated and drawn at a plate temperature of 70 ° C. Next, the temperature of the obtained cup was set to 40 ° C., and ironing was performed at a mold temperature of 80 ° C. to obtain a 350 ml size seamless can.

  Table 3 shows the measurement results of the adhesion strength after remelting of the product of this example, the resistance to cracking, the releasability of the inner film of the can and the processing punch, and the impact resistances I and II. As is clear from Table 3, the film of this example was excellent in adhesion. In addition, the laminate plate of this example was excellent in the resistance to peeling and releasability, and the aluminum can of this example was excellent in impact resistance.

[Example 2]
Except that the ratio of the layer thickness of the resin layers (I) and (II) was 50/50, and the addition amount of the antioxidant and polyethylene wax to the resin layer (I) was 800 ppm, respectively, A metal plate laminating film having the structure shown in Table 1 was obtained. Next, a remelt aluminum plate was produced in the same manner as in Example 1 and canned to obtain a 350 ml size seamless can.

  Table 3 shows the measurement results of the adhesion strength after remelting of the product of this example, the resistance to cracking, the releasability between the can inner film and the processing punch, and the impact resistance. As is clear from Table 3, the film of this example was excellent in adhesion. In addition, the laminate plate of this example was excellent in the resistance to peeling and releasability, and the aluminum can of this example was excellent in impact resistance.

[Example 3]
A metal plate having the structure shown in Table 1 in the same manner as in Example 1 except that the raw material of the resin layer (II) was PET-I (10) / olefin A / olefin C = 94/3/3 (% by weight). A film for laminating was obtained. Next, a remelt aluminum plate was produced in the same manner as in Example 1 and canned to obtain a 350 ml size seamless can.

  Table 3 shows the measurement results of the adhesion strength after remelting of the product of this example, the resistance to cracking, the releasability between the can inner film and the processing punch, and the impact resistance. As is clear from Table 3, the film of this example was excellent in adhesion. In addition, the laminate plate of this example was excellent in the resistance to peeling and releasability, and the aluminum can of this example was excellent in impact resistance.

[Example 4]
A metal plate having the structure shown in Table 1 in the same manner as in Example 2 except that the raw material of the resin layer (II) was PET-I (10) / olefin A / olefin D = 94/3/3 (% by weight). A film for laminating was obtained. Next, a remelt aluminum plate was produced in the same manner as in Example 2 and canned to obtain a 350 ml size seamless can.

  Table 3 shows the measurement results of the adhesion strength after remelting of the product of this example, the resistance to cracking, the releasability between the can inner film and the processing punch, and the impact resistance. As is clear from Table 3, the film of this example was excellent in adhesion. In addition, the laminate plate of this example was excellent in the resistance to peeling and releasability, and the aluminum can of this example was excellent in impact resistance.

[Example 5]
A metal plate having the structure shown in Table 1 in the same manner as in Example 3 except that the raw material of the resin layer (II) was PET-I (10) / olefin B / olefin E = 94/3/3 (% by weight). A film for laminating was obtained. Next, a remelt aluminum plate was produced in the same manner as in Example 3, and canned to obtain a 350 ml size seamless can.

  Table 3 shows the measurement results of the adhesion strength after remelting of the product of this example, the resistance to cracking, the releasability between the can inner film and the processing punch, and the impact resistance. As is clear from Table 3, the film of this example was excellent in adhesion. In addition, the laminate plate of this example was excellent in the resistance to peeling and releasability, and the aluminum can of this example was excellent in impact resistance.

[Example 6]
It shows in Table 1 like Example 3 except having made the raw material of resin layer (II) into PET / PET-I (10) / olefin A / olefin B = 47/47/3/3 (weight%). A film for laminating a metal plate was obtained. Next, a remelt aluminum plate was produced in the same manner as in Example 3, and canned to obtain a 350 ml size seamless can.

  Table 3 shows the measurement results of the adhesion strength after remelting of the product of this example, the resistance to cracking, the releasability between the can inner film and the processing punch, and the impact resistance. As is clear from Table 3, the film of this example was excellent in adhesion. In addition, the laminate plate of this example was excellent in the resistance to peeling and releasability, and the aluminum can of this example was excellent in impact resistance.

[Comparative Example 1]
A metal having the structure shown in Table 2 in the same manner as in Example 1 except that the raw material of the resin layer (II) was PET-I (10) = 100 (wt%) (raw material excluding olefin from Example 1). A plate laminating film was obtained. Next, a remelt aluminum plate was produced in the same manner as in Example 1 and canned to obtain a 350 ml size seamless can.

  Table 3 shows the measurement results of adhesion strength, repelling resistance, releasability between can inner film and processing punch, and impact resistance of the product of this comparative example. As apparent from Table 3, although the product of this comparative example was excellent in adhesion, crack resistance and releasability, the impact resistance was remarkably inferior.

[Comparative Example 2]
A metal plate laminating film having the structure shown in Table 2 was obtained in the same manner as in Example 3 except that the water-dispersed copolyester resin was not applied. Next, a remelt aluminum plate was produced in the same manner as in Example 3, and canned to obtain a 350 ml size seamless can.

  Table 3 shows the measurement results of adhesion strength, repelling resistance, releasability between can inner film and processing punch, and impact resistance of the product of this comparative example. As is clear from Table 3, the product of this comparative example was excellent in adhesion resistance, but was inferior in adhesion and releasability. The impact resistance was not evaluated because the release property of the product was extremely inferior.

[Comparative Example 3]
A metal plate laminating film having the structure shown in Table 2 was obtained in the same manner as in Example 3 except that the coating thickness of the water-dispersed resin was 50 nm. Next, a remelt aluminum plate was produced in the same manner as in Example 3, and canned to obtain a 350 ml size seamless can.

  Table 3 shows the measurement results of adhesion strength, repelling resistance, releasability between can inner film and processing punch, and impact resistance of the product of this comparative example. As is clear from Table 3, the product of this comparative example was excellent in adhesion resistance, but was inferior in adhesion and releasability. The impact resistance was not evaluated because the release property of the product was extremely inferior.

[Comparative Example 4]
A metal plate laminating film having the structure shown in Table 2 was obtained in the same manner as in Example 3 except that the raw material of the resin layer (I) was changed to PET-I (10) = 100 (% by weight). Next, a remelt aluminum plate was produced in the same manner as in Example 3, and canned to obtain a 350 ml size seamless can.

  Table 3 shows the measurement results of adhesion strength, repelling resistance, releasability between can inner film and processing punch, and impact resistance of the product of this comparative example. As can be seen from Table 3, the product of this comparative example is excellent in adhesion and crack resistance, but when a remelt aluminum plate is made, the inner surface film of the can is poorly stretched and the releasability is remarkably inferior. It was. The impact resistance was not evaluated because the release property of the product was extremely inferior.

[Comparative Example 5]
A metal plate laminating film having the structure shown in Table 2 was obtained in the same manner as in Example 3 except that the antioxidant content of the resin layer (I) was 100 ppm. Next, a remelt aluminum plate was produced in the same manner as in Example 3, and canned to obtain a 350 ml size seamless can.

  Table 3 shows the measurement results of adhesion strength, repelling resistance, releasability between can inner film and processing punch, and impact resistance of the product of this comparative example. As is apparent from Table 3, although the product of this comparative example was excellent in adhesion, a bumping phenomenon (so-called cracking) occurred during remelting of the remelted aluminum plate, and the cracking resistance was remarkably inferior. The releasability and impact resistance were not evaluated because the releasability of the product was extremely inferior.

[Comparative Example 6]
A metal plate laminating film having the structure shown in Table 2 was obtained in the same manner as in Example 3 except that the polyethylene wax content of the resin layer (I) was 100 ppm. Next, a remelt aluminum plate was produced in the same manner as in Example 3, and canned to obtain a 350 ml size seamless can.

  Table 3 shows the measurement results of adhesion strength, repelling resistance, releasability between can inner film and processing punch, and impact resistance of the product of this comparative example. As is apparent from Table 3, the product of this comparative example is excellent in adhesion and resistance, but when a remelt aluminum plate is made, slippage of the inner film of the can occurs and releasability is remarkably inferior. It was. The impact resistance was not evaluated because the release property of the product was extremely inferior.

  The metal plate laminating film of the present invention is highly satisfactory for adhesion, releasability, armpit resistance, and impact resistance, so it is extremely useful for preventing corrosion of metal containers such as soft drinks, beer and canned foods. Useful.

Claims (7)

Resin layer (I) containing 20 to 80/80 to 20% by weight of crystalline polyethylene terephthalate / crystalline polybutylene terephthalate and containing 500 ppm or more of an antioxidant and a lubricant, and 180 ° C. or more And a resin layer (II) in which an olefin polymer is dispersed in the form of particles having an average particle diameter of 3.0 to 5.0 μm are laminated on a polyester resin having a melting point of, and further bonded to a metal plate of the resin layer (II) The resin layer (III) made of water-dispersed copolyester resin is laminated on the intended side, and the total thickness of the resin layer (I) and the resin layer (II) is 10 to 50 μm. The ratio of the thickness of the layer (I) / resin layer (II) is 30 to 70/70 to 30, the thickness of the resin layer (III) is 5 to 40 nm, and the resin layer (II) Ester mixing weight ratio of the resin and the olefinic polymer is 91: 9-99: metal plate laminating film, which is a 1. The adhesion strength between the film and the metal plate is 18 N / 15 mm or more measured after the metal plate laminating film is pasted on the metal plate, re-melted by heat above the melting point of the film, and then rapidly cooled. The metal plate laminating film according to claim 1 . The melting point of the resin layer (I) is 200 to 260 ° C, and there are at least two melting peaks of the resin layer (I), and the metal plate laminating film according to claim 1 or 2 . Metal plates laminated film according to any one of claims 1 to 3, the Tg of the water-dispersible copolymerized polyester is characterized in that it is a 40 to 80 ° C. of the resin layer (III). The metal plate laminating film according to any one of claims 1 to 4 , wherein the olefin polymer comprises polyethylene and / or an ethylene copolymer. A film laminate metal plate obtained by laminating the metal plate laminate film according to any one of claims 1 to 5 on a metal plate. A metal container obtained by molding the film-laminated metal plate according to claim 6 .